An old friend has returned to Arizona farming. Grain sorghum is among a long list of crops offering good returns these days, and Marana, Ariz. farmer Tom Clark of Clark Farms is welcoming back the old-timer.

“The main reason I’m growing grain sorghum is the price,” said Clark who also grows cotton, wheat, and barley on his 1,600 leased acres located north of Tucson. Like many of his peers, Clark is an old hand at grain sorghum. He grew grain sorghum about 20 years ago. It disappeared from his farm, replaced by crops with better income potential.

Clark signed a one-year contract to grow 150 acres of grain sorghum for $9 per hundredweight for Arizona Grain, Casa Grande, Ariz. He planted a Pioneer variety in early July after wheat. Some sorghum was minimum tilled into the wheat stubble. Yields averaged about 2.25 tons per acre.

Insects never pestered the crop and a single, hooded-sprayer application of the herbicide Clarity handled a few broadleaf issues. Water usage was 2.5 to 3 acre-feet, a bit lower than expected due to rains in September and October.

At harvest in late December, Clark learned that that his crop would help fuel Arizona’s first ethanol production facility, Pinal Energy LLC, located near Maricopa, Ariz., south of Phoenix. The ethanol plant, owned by Arizona Grain, went into production in July 2007.

Clark is one of an increasing number of growers in Arizona getting onto the grain sorghum bandwagon or considering such a move. Clark is so enthralled with the prospects of grain sorghum this year that he signed another contract with Arizona Grain for 100 acres for $11.30 per hundredweight. He’ll plant the Golden Acres Genetics 737 variety in July.

The economic return for grain sorghum gives Clark another rotation crop. That’s been a challenge since Clark Farms is located at about 2,000 feet above sea level.

“With the elevation in Marana it’s hard to double crop anything,” Clark said. “If you can get the grain planted early, cut early enough, and plant grain sorghum by July 15, you can still make a decent crop.”

This January Clark planted Solar, a low input Arizona barley variety, for planting seed for Barkley Seed Inc. in Yuma, Ariz., on the acreage he plans to plant in grain sorghum this summer. The January-planted barley headed out in early April with minimum irrigation. Following harvest, Clark will minimum till the sorghum into the ground using Yetter row openers to open up the barley stubble for drilling in the sorghum.

Another reason Clark opted for grain sorghum is improvements in soil. “The combine cuts underneath the head so the stalk is left for turning over into the ground to create humus and improve soil fertility,” Clark said.

Clark’s optimism for double cropping sorghum is tempered by his concerns to harvest in a timely manner.

“The issue that concerns farmers in Marana is we seem to be the stepchild in getting grain harvested in a timely manner because we plant later than farmers in Maricopa, Pinal, and Yuma counties,” Clark said. “Sometimes the harvesters don’t get down to Marana in time even though our grain is ready. Also in the past there have been bottlenecks at the scales at the granary so we’re afraid that may happen again this year.”

Statewide, the USDA-National Agricultural Statistics Service-Arizona office predicts that Arizona’s 2008 grain sorghum acreage would likely mirror last year’s acreage of about 45,000 acres. However, there are signs it may be more.

The Pinal Energy ethanol plant requires about 18 million bushels of grain annually to achieve its annual 50-million-gallon production output. Last year 95 percent of the plant’s grain requirements were filled by corn railed in from the Midwest into Arizona. The other 5 percent was locally grown grain. Arizona Grain President Eric Wilkey hopes to triple that amount to 15 percent this year.

“Our goal is to support local grain production because we’re a local company,” said Wilkey. “We’d rather rely on a local supplier than a Midwestern producer, railroad, and all the other things that stand in between us and the grain supply. Can we get 100 percent of our grain needs grown locally? No, we have to rely on both.”

Price is the bottom line for Wilkey and he’ll buy whatever is the least costly.

“If we can buy grain locally at the same price as rail grain, I’d prefer local grain because I don’t run the risk of the train derailing and the corn not arriving,” Wilkey said.

Every kernel of grain sorghum purchased by Arizona Grain is used in the ethanol plant.

Arizona grain sorghum was run through the ethanol plant last November through this February and worked well, Wilkey noted.

Grain sorghum is not equivalent to corn in the ethanol conversion process. Sorghum requires additional enzymes to produce ethanol, but yields the same amount of ethanol.

Two byproducts of the ethanol process are CO2 and distiller’s grain. Most of the wet distiller’s grain is sold within a 60-mile radius as a livestock feed ingredient. A small amount is dried, also for livestock use.

The minimum quality requirement for grain sorghum in ethanol production is No. 2 grade and 14 percent moisture or less, Wilkey said. Arizona Grain pays a 5-cent premium per hundredweight if the planting seed is purchased from the company.

The vast majority of the grain sorghum purchased is within a 100-mile radius of the ethanol plant. Some grain sorghum is also grown in the Willcox and Yuma areas.

In Arizona two planting windows exist for grain sorghum — late February to March 15 and July 1-20. Average yields are like what Clark gathered, 2.5 tons per acre, Wilkey said.

According to Tim Knudsen, Arizona Grain’s marketing manager, the Golden Acres 737 variety is the most popular sorghum seed planted in Arizona. “737 is a medium to early maturity variety which produces large berries on the head that are excellent for ethanol production.” Other good grain sorghum varieties for ethanol conversion include Golden Acres 3552, 3694, 3827, plus Pioneer’s 84G62 and 85G01.

Barkley Seeds Inc. also sells grain sorghum planting seed. General manager Michael Edgar said grain sorghum plantings could increase in Yuma County. “I know there are people talking about it,” Edgar said. “How many will turn words into action? That’s what I don’t know.”

Cattle feed yards are reportedly paying good money for the stubble coming off harvested grain sorghum fields which helps the grower in his return per acre. Most sorghum grown in Yuma County is grown on the east side due to its closer proximity to Maricopa and related lower freight charges.

Barkley Seed offers the Garrison & Townsend Inc. variety GS125. According to Alan Rubida, Barkley’s field seed division manager, the variety is excellent for green chop for livestock and for grain for ethanol. Yields range from 3.5 to 4 tons per acre.

Sorghum data

University of Arizona Extension Agronomist Mike Ottman released a guide called “Growing Grain Sorghum in Arizona” last spring. Ottman points out that grain sorghum is more resistant to salt, drought, and heat stress than many other crops.

Grain sorghum can be planted in row spacing ranging from 6 to 40 inches apart or in twin rows in a variety of configurations. Bed or flat ground plantings work fine.

The optimum seeding rate for grain sorghum is about 10 pounds of seed per acre assuming a seed size of 14,000 seeds per pound and 70 percent emergence. Seed size varies depending on the hybrid, so the seeding rate on a pound-per-acre basis should be decreased for smaller seed and increased for larger seed. The goal is achieving a 100,000-plant density per acre.

The optimum seeding depth is 1-2 inches. Seed deeper on lighter than heavier soils or if seeding into moisture rather than irrigating up.

Grain sorghum usually requires about 150 pounds of nitrogen per acre with about a quarter to half applied at planting time. The actual nitrogen requirement depends on grain yield, residual nitrogen in the soil and irrigation water, plus other factors. Phosphorus fertilizer is generally not required, unless the soil phosphorus level is very low and planting occurs in the cooler part of the spring.

Sorghum requires adequate soil water for maximum yields even though the crop is drought resistant. The amount of water used by sorghum in a late June planting in Mesa, Ariz. was measured at 25 inches. Assuming an irrigation efficiency of 70 percent, the actual amount of irrigation water needed to meet this water use is 36 inches.

Weeds in grain sorghum reduce grain yield, harbor insects and diseases, and create problems at harvest. Weeds are controlled by tillage or herbicides.

Many insects can feed on sorghum, but chemical treatment may not be warranted unless severe damage occurs. Severe insect damage is most common when sorghum is planted late or following a corn or sorghum crop. Some insects that may infest sorghum are the Southwestern corn borer, lesser stalk borer, corn leaf aphid, greenbug, sorghum midge, corn earworm, fall armyworm, stink bugs, cutworms, flea beetles, and spider mites.

Grain sorghum grown in Arizona usually is not significantly damaged by diseases. However, a head smut, maize dwarf mosaic, and Yuma root rot disease are a few diseases that can be damaging. Fungicide applications usually are not economical for grain sorghum diseases. The most effective control measures are hybrid resistance and allowing at least three years between sorghum crops.

When to harvest sorghum can be a difficult decision due to uneven maturity. Also, depending on the hybrid, the stalks and leaves may still be green when the grain is ready for harvest. Sorghum can be harvested when grain moisture content is 15 percent to 20 percent, but the grain cannot be stored safely above a moisture content of 13 percent to 14 percent. Sorghum grain readily absorbs moisture from the atmosphere, and grain moisture content can change a few percentage points during the day. Sorghum grain is brittle and more easily cracked than grain of wheat or barley so care must be taken when adjusting the combine.